Photographic printing machine



Dec. 3, 1940. A M, ERNST TAL 2,223,341

PHOTOGRAPHI C PRINTING MACHINE Filed Nov. 1'?, 1938 2 Sheets-Sheet l DeC- 3, 1940 A. M. ERNST l-:TAL 2223,341

PHOTOGRAPHI C PRINT ING- MACHINE Fled NOV. 17, 1938 2 Sheets-Sheet 2 BY WALTER M.ERNST www 9" h? ATTORNEYS Patented Dec. 3, 1940 UNITED STATES vPATENT OFFICE Allan M. Ernst and Waltier M. Ernst, Cleveland, 0h o Application November 17, 1938, Serial No. 241,004

11 Claims.

This invention relates to machines for making photographic prints, and especially to a relatively inexpensive machine suitable for economically making prints or copies of all sorts of documents.

Ordinary printing machines where the material is interposed between plane surfaces are not generally satisfactory for making large prints because wrinkles frequently occur and it is very difilcult to obtain uniform, satisfactory contact over large areas. 'I'he large power driven machines where the prints are held between a rotating cylinder and a conveyor belt. are relatively costly and consequently unavailable for many purposes.

It is, therefore, an object of this invention to provide photographic printing machines which provide uniform contact over large areas and which are suitable for economically making prints of all sizes.

It is another object of this invention to provide photographic printing machines wherein there is no tendency for slippage between the negative and printing paper.

It is a further object of this invention to provide photographic printing machines wherein the entire exposure area is substantially evenly lighted.

This invention is shown in the accompanying drawings in which similar characters of reference denote corresponding parts, in which:

Figure 1 is a front elevation of the device with parts broken away to show its internal construction;

Fig. 2 is a section on the line 2-2 of Fig. 1 and shows the form of the invention wherein the nexible work receiver is attached to a stationary element in-the device;

Fig. 3 is an enlarged sectional view of a portion of the machine shown in Fig. 2, and shows the hinge construction and the method of applying work to the machine and the position occupied by the flexible work receiver in the open position;

Fig. 4 is a fragmentary sectional view of a portion of the machine and shows a method for attaching filters when these are desired Fig. 5 is a fragmentary end view with parts broken away;

Fig. 6 is a fragmentary section in the vicini-ty of the hinge portion of a modified form of the device, wherein the flexible work receiver is attached to a movable. element; of the device; and

Fig. 7 is a fragmentary section of the open machine in the vicinity of the hinges, and shows the method for attaching and the position occupied by the flexible work receiver in the open position.

Referring more particularly to the drawings, the machine comprises a stationary frame 2 carrying the bottom 3, the ends 4 and 5, and the sides 6 and 1, a curved transparent member i0 which is fastened to the movable frame 8, an auxiliary frame il, a flexible work receiver i2, and a light source 9.

The movable 4frame 8 is rotatably mounted on the stationary frame 2 by means of the hinge I3 which is parallel to an element of the surface of said transparent member and is preferably located near the edge of the curved member i0, an extension thereof as in Figs. 6 and 7, or at a slightly greater distance from the center of curvature as in Figs. 2 and 3. The curved, transparent member I0 is preferably a portion of a. cylinder and it is fastened to the movable frame 8 by means of the end supports I4 which are preferably opaque and adapted to maintain a dust-tight seal around the edges of the curved, transparent member IU.

The light source 9 may be a series of bulbs, or it may be of the luminous tube type, supported at each end by the mounting brackets i5 which are fastened to the end supports i4 and are adapted to make electrical connection between the terminals i6 and the electrodes of the light source. The light source 9 is preferably mounted coaxially with the curved or cylindrical portion of the transparent member so as to be normally equidistant to all points of the surface of the member and thus provide a substantially uniform illumination over the printing area. Means, such as a ground glass, a filter, or a diffuser i1, may be provided for varying the intensity, diffusion, and character of the illumination applied to the printing surface. The filters may be mounted to be revolved about the light source 9 and may be conveniently secured by means of the clips I8 which are fastened to the ends of the filter i1 and are adapted .to fit the light source 9 or suitable mountings.

The auxiliary frame II is fastened to the movable frame 8 by means of the hinge I9, and it is provided with a suitable top member or members 20, and ends 23 and 24 which are adapted to cooperate with each other and the frame Il to form a cover for the movable frame 8 and prevent dust from settling on the inner curved surface of the transparent member I0. 'I'he top member 20 may carry a window 31 which may be used for observing the work material before or during the printing operation. The latch 3| may CTI be used for securing the auxiliary frame II to the lmovable frame 8. An automatic timing device may be inserted in the cover 20 and connected with a light circuit so as to interrupt the 5 current which flows between the connector 34 and the light source 9 over the wires 35 at a denite predetermined time. Ii desired a means, such as a variable resistance 36, may be provided to vary the voltage on the light source 9.

One of the features of the present invention is the flexible work receiver I2. A convenient form for such a receiver is shown in Fig. 2 in which one end of the flexible work receiver,

which may be a sheet of canvas or fabric, is fastened to the frame 2 by any suitable securing means 2|. It passes over the idler roll 26 and is maintained under tension by means of the tension roll 21 which contains a suitable coil spring 28 and is adapted at all times to take up any slack and maintain the flexible work receiver I2 taut. The roll 28 may be fastened to the frame 2 and preferably is located so as to maintain thel surface of the flexible work receiver in the piane of the surface of the top of the frame 2 when the cover is in the open position as shown in Fig. 3. A work rest 29 may be provided and as shown in Fig. 2 is hinged to the frame 2 by means of the hinge 30. It may be held in operative position by a suitable brace 39 or it may hang in inoperative position.

In Figs. 6 and 7 is shown a modiiied form ou? securing the cover to the stationary frame member and attaching the work receiving device. In this form the portion 8 of the movable frame carries a framing bar 8a which israbbeted to receive the edge of the transparent member I0. The flexible work receiver I2 is secured by any suitable means 2I to the bar 8a. The hinge I3 for the parts 8, 8a is so located that the axis of 40 the hinge is substantially in the plane of or forms an element of the projected curved transparent member I0. When the cover` is moved down from a position shown in Fig. 7 it will be seen that the transparent cylinder will quickly clamp the edges of the negative and sensitized sheet and firmly hold them while the cover is being lowered to printing position.

While the work receiving member has been shown as a flexible sheet secured at one end and held by a tensioning roll at the other end, it is to be understood that various modifications may be made in which a transparent member of the cylindrical type and the iiexible work receiver may be mounted or moved to tightly grasp and hold the work material with uniform contact.

While the source of light is shown as a luminous tube extending substantially the length of the curved transparent member, it will be seen that a series of luminescent bulbs, preferably of the inside frosted type, may be utilized in which case the incandescent filaments or bulbs should be disposed substantially along the axis of curvature of the cylindrical or partially cylindrical transparent member.

In the operation of the invention the frame 8 is raised to the upper position, whereupon the slack in the exible work receiver I2 is taken up by the roll 21 and the portion of the flexible work receiver between the roll 26 and the point where T0 it is attached to the frame is held substantially in a horizontal position under considerable tension. A negative or original 32 to be printed and a sensitized sheet 33 of suitable size, are placed on the fiat portion of the flexible work receiver as illustrated in Fig. 3.

The movable frame 8 is then lowered, whereupon th`e curved surface of the transparent member I 0 comes` in contact with the negative and rmly holds the negative and sensitized sheet together between the member I0 and the exible work receiver I2. During the closing action one edge of the Work is first held or clamped between the curved member I 0 and the flexible work receiver I2. Upon further closing movement of the cover there is a marked ironing action which smooths out any wrinkles that may be present in the work material. This smoothing or ironing action irons out the wrinkles and maintains uniform contact between the negative and the sensitized paper over the whole area, and is accentuated when the hinges for this transparent member are located away from the axis of the curved or cylindrical member.

If it is desired to modify the character or intensity of the light source 8 the variable resistance 36 is adjusted to the desired value and a suitable filter or diffuser I1 is interposed between the light source and the curved transparent member II). The printer is then closed, whereupon the work material is held firmly between the flexible work receiver and the curved transparent member as shown in Figure 2. The timer 25 is then set at a predetermined value and the desired exposure time is automatically obtained. The material may then be removed and developed in the customary manner.

It may be seen that, while there is a relative bodily movement between the work receiver I2 and the curved transparent member III, there is no tendency for slippage between the surface of the curved transparent member and the flexible Work receiver. Thus there is no tendency for the negative 32 to slip with reference to the sensitized material 33 and prints with positive register are thus obtained. The substantially uniform lighting and perfect contact obtained with our invention eliminate the variation in density of the lines of the recorded image, and the uneven exposures frequently obtained when large prints are produced. When in the printing position the work receiver conforms to the curvature of the curved transparent member I0 and maintains perfect contact over the entire printing area. The pressure between the work receiver and the curved member may be varied by adjusting the tension of the spring 28 in the tension roll 21.

It has been found that this invention maintains substantially uniform contact over large or small areas and that large and small prints alike are produced with extreme accuracy and relative ease and economy. It is advantageous for use in large and small establishments alike and is adapted for making photographic prints in general including Vandykes, copies of all sorts of l documents, and blueprints. It is also suitable for making curved oiiset printing plates and in their preparation a vacuum printing frame is unnecessary, due to the ironing effect and positive contact secured over the entire exposure area.

Although but two specific embodiments of the invention are herein shown and described, it is to be understood that numerous details may be altered or omitted without departing from the spirit of the invention as defined in the following claims.

What we claim is:

1. A photographic printer comprising a supporting structure, a pair of spaced supports carried by the structure, a flexible work receiver having a portion extending between the supports and having fixed and movable ends, resilient means having connection with the movable end of the receiver to yieldingly hold the same and thereby maintain the portion of the receiver between the supports under tension in a normally at plane position, a cylindrically curved light'transmitting member having hinged means mounting the same on the structure for pivotal movement about an axis substantially at the xed end of the work receiver and so that the convex side of said member is movable against said normally fiat portion of the receiver to displace the latter to a curved printing position corresponding to the curvature of the light transmitting member, a light source, and means mounting the light source on the concave side of the curved member opposite the work receiver and for movement with the curved member to printing position.

2. A photographic printer comprising a supporting structure, a fiexible work receiver, spaced means carried by the structure to support the work receiver, resilient means for tensioning a portion of the work receiver between the spaced supporting means to normally retain the surface of said portion in a substantially fiat plane position, at least one end of said portion of the work receiver being yieldable to permit displacement of the receiver from said fiat plane position, a curved light transmitting member having concave and convex sides, pivot means carried by the structure and mounting said member for rotative movement bodily relative to said work receiver about an axis substantially in said plane whereby the light transmitting member can be moved bodily to bring the convex side thereof against said portion of the work receiver and displace the latter, and a light source having means for supporting the same on the concave side of the light transmitting member.

3. A photographic printer comprising a curved iight transmitting member having convex and concave sides, a light source and means for supporting the same on the concave side of the member, a deformable work receiver on the convex side of the curved member, means for resiliently supporting the work receiver with a potrion of the surface thereof in a normally substantially at plane position and which permits said portion to be deformed to a curved position, and means for supporting the light transmitting member for bodily movement against said normally flat surface portion of the work receiver to displace said portion of the work receiver.

4. Al photographic printer comprising a. yieldable work receiver, spaced supports, resilientmeans for holding a portion of the work receiver with the surface thereof tensioned between said supports in a normally substantially fiat plane position and which permits said portion to be deformed to a curved position, a curved light transmitting member having convex and concave sides, means for supporting said member for bodily movement of the convex side thereof against said fiat portion of the work receiver to displace the work receiver so that said surface portion thereof corresponds in curvature to the convex side of the light transmitting member, a light source, and means supporting said source on the concave side of the `light transmitting member for boily movement therewith.

5. A photographic printer comprising a curved light transmitting member having convex and concave sides, a light source and means for supporting the same on the concave side of the member, a iiexible work receiver on the convex side of the curved member, spaced means supporting a portion of the work receiver in a normally fiat position, means for yieldingly retaining the at portion of the receiver under tension between said spaced supporting means, and means mounting the curved member for bodily movement toward and away from the work receiver, the movement of the curved member toward the receiver being directed between said spaced supporting means to displace said portion of the receiver from its normally fiat position.

6. A photographic printer comprising a curved light transmitting member having convex and concave sides, a light source and means for supporting the same on the concave side of the member, a fiexible work receiver on the convex side of the curved member, spaced means supporting a portion of the work receiver in a normally iiat position, means for yieldingly retaining the fiat portion of the receiver under tension between said spaced supporting means, and pivot means for mounting the curved member for pivotal movement about an axis adjacent the surface oi.' the curved member and toward and away from the work receiver, the pivotal movement of the curved member toward the receiver effecting a bodily movement of the curved member between said spaced supporting means to displace said portion of the receiver from its normally iiat position.

rI. A photographic printer comprising a light transmitting member having a substantially cylindrical surface, an elongated light source disposed substantially along the longitudinal axis of the light transmitting member and means supporting said source for movement with said member, a flexible work receiver having means associated therewith to maintain a portion of the same under tension and normally yieldably supported in a substantially flat plane position on the convex side of the light transmitting member. and means for supporting the curved member for bodily movement transverse to said plane of the work receiver to displace the flexible work receiver from its normally fiat plane position to a curved position of which the fiat position is a subtending chord. K

8. A photographic printer comprising a iiexible work receiver, spaced substantially parallel elements for supporting a portion of the work receiver in a normally fiat plane position and which permits deformation of the receiver therebetween, a curved light transmitter member having concave and convex sides, means supporting the light transmitting member for pivotal movement about an axis adjacent the plane of the fiat work receiver and near one of said elements so that the convex side of the light transmitting member is toward the work receiver and said member can be shifted bodily to move the convex side thereof into engagement with said portion of the work receiver to displace the latter from its fiat plane position, and alight source having associated means for supporting the same on the concave side of the light transmitting member.

9. A photographic printer comprising a flexible work receiver, spaced substantially parallel elements for supporting a portion of the work receiver in a normally fiat plane position and 'which permits deformation of the receiver therebetween, a curved light transmitting member having concave and convex sides, means supporting the light transmitting member for pivotal movement about an axis adjacent the plane oi the fiat work receiver and near one of said elements so that the convex side of the light transmitting member is toward the work receiver and said member can be shifted bodily to move the convex side thereof into engagement with said portion of the work receiver to displace the latter from its iiat plane position, a light source disposed on the concave side oi the light transmitting member, and means for supporting said source for pivotal movement about said axis.

10. A photographic printer comprising a supporting structure, a curved light transmitting member having concave andl convex sides, a light being at a distance from the axis of curvature o! the light transmitting member at least substantially equal to the radius oi curvature of said member. v

11. A photographic printing machine comprising a supporting structure, a light source, a ilexibie work receiver having a yieldable portion with ixed and movable ends, a curved light transmitting member concave on one side and convex on the other side, and means mounting the curved member on the structure for rotation into printing position about a pivot which is substantially at the xed end of the work receiver to permit rotative movement oi.' the convex side o! the curved member against said portion of the work receiver, and resilient means at the movable end ofthe work receiver to maintain the same under tension and to normally yieldably hold the same in a substantially at plane position from which the receiver is displaced by movement of the light transmitting member into printing position.

ALLAN M. ERNST. WALTER M. ERNST. 

